For that time period, contact the main Detroit Public Library. They charge $15.00 per obit whether they find them or not.

http://www.detroit.lib.mi.us/research-resources

Or if your library participates in the Inter Library Loan (ILL) program, you could order the films of the papers. For that time period, I have found that the Detroit News seems to have more death notices, followed by the Detroit Free Press.

http://www.detroit.lib.mi.us/specialservice/interlibrary-loa...

Or you could try the Detroit Society for Genealogical Research to see if someone would look for them.

http://www.dsgr.org/